The maximum number of items to return. If Amazon DynamoDB hits this limit while scanning the table, it stops the scan and returns the
matching values up to the limit, and a LastEvaluatedKey to apply in a subsequent operation to continue the scan. Also, if the scanned
data set size exceeds 1 MB before Amazon DynamoDB hits this limit, it stops the scan and returns the matching values up to the limit, and a
LastEvaluatedKey to apply in a subsequent operation to continue the scan.